docs: def insert(collection_name, docs, check_keys, safe, last_error_args):
      """Get an **insert** message.
      """
      data = __ZERO
      data += bson._make_c_string(collection_name)
      bson_data = "".join([bson.BSON.encode(doc, check_keys) for doc in docs])
      if not bson_data:
          raise InvalidOperation("cannot do an empty bulk insert")
      data += bson_data
      if safe:
          (_, insert_message) = __pack_message(2002, data)
          (request_id, error_message) = __last_error(last_error_args)
          return (request_id, insert_message + error_message)
      else:
          return __pack_message(2002, data)